Concept of Maintenance Management Assignment Question and Answers
After studying this unit the student will be able to:
- To understand maintenance management in a production department
- To know various tasks of maintenance manager
- To make aware of maintenance scheduling process in production department
- Objectives of Maintenance Management
- Planning Maintenance
- Requirements for Maintenance Management
- Problems of improper planning
- Schedule of Maintenance Program
- Organization for effective planning
- Supervisory control
- Tasks of Maintenance Manager
- Preventive Maintenance
- Procedure of Preventive Maintenance
- Corrective Maintenance
- Maintenance Scheduling
- Five Fold Program
- Using data processing in maintenance
- Review questions
In order to understand and appreciate maintenance Management, we must recognize that in some way all maintenance jobs are planned. In the absence of a planning system, the job planning function may be the responsibility of craft foremen who may also perform the attendant paperwork in addition to supervision of craft personnel. In other instances, the craftsmen do their own job planning after receiving the job Assignment from their foreman. The engineering department, with appropriate drawings and bills of material, may plan technically complicated or costly jobs. The most common practice usually involves a combination of these methods with varying degrees of paperwork. Obviously, the size and complexity of the maintenance operation must be considered in the approach to maintenance control.
Management and control of a small maintenance group of 10 to 15 craftsmen can be accomplished on an informal basis. On the other hand, a maintenance force in excess of 25 to 30 men presents complications from coordination and planning standpoint. Unfortunately the informal control approach is too often used in large, complex organizations even though the magnitude of the operation may have long since exceeded manageable dimensions. Since maintenance work is variable in both nature and content, job planning usually offers the greatest opportunity for improvement. At the same time, however, planning also presents one of the most difficult problems encountered in maintenance.
‘Maintenance’ is the routine, recurring work which is required to keep a facility in such a condition that it may be utilized at its original or designed capacity and efficiency. It includes the application of management methods and requires systematic attention.
OBJECTIVES OF MAINTENANCE MANAGEMENT:
- To minimize maintenance cost, along with proper protection of capital investment.
- To have optimum utilization of resources and operating time.
- To provide a means of collecting cost and other information that will be useful in improving maintenance and other performance.
- To establish methods of evaluating work performance and this will be useful to management in general and to maintenance supervisors in particular.
- To improve the skills of supervisors and subordinates through proper training.
- To aid in establishing safe working conditions for both operating department and maintenance personnel by establishing and keeping proper standards.
PLANNING & MAINTENANCE: ‘The process used to develop a course of action. Effective maintenance planning involves the development of a course of action that includes all maintenance, repair, and construction work. It requires the identification of a number of factors’.
- The scope of the job: Most requests received by the maintenance department are not sufficiently definitive. A request to “repair steam leak” may require replacement of a valve, of a pipe, or of packing—or perhaps the simple tightening of the connection. To the extent possible, work to be done should be outlined clearly and completely. Drawings or sketches should be made available if these are necessary to identify the job.
- The location of the job: The exact location where the work is to be performed should be identified through building number, department number, machine number, or some other meaningful designation.
- The job priority: Priority control is required so that the job can be scheduled in its proper sequence. While each operation or facility has varying requirements, definite rules can be established to provide guidelines for job priorities.
- The methods to be used: Effective planning also requires a definition of methods. “Purchase and install” is considerably different from “fabricate and install.” Whether shop fabrication or field fabrication is involved is likewise important. Welding instead of fastening with bolts requires different craft skills. The use of hand tools in place of machine tools may or may not be advisable. Although many jobs are clear-cut and require the usual craft methods, there are also instances where several choices may exist.
REQUIREMENTS FOR MAINTENANCE MANAGEMENT:
- Materials: Maintenance Manager must ensure that necessary materials are available.
- Tool: Manager should identify the requirement of special tools if any, so that they are available when the job is started. Torque wrenches, hoists, slings, or jacks are special job requirements and should be specified.
- Craft: Maintenance Manager should see that craft lines are followed, the various crafts required to perform the work should be identified.
- Manpower: The number of man-hours required to perform the work should be determined for each job, which is necessary for scheduling control.
PROBLEMS OF IMPROPER PLANNING
- Lack of Communications. Job instructions received by the workers should not be incomplete.
- Incomplete planning leads to confusion, delays, and lost time result
- Improper planning results in poor work performance, failure to satisfy the requester, frayed tempers, and high costs.
- Improper management of materials leads to false starts, delays, or makeshift repairs may result.
- Materials may be required which are not carried in stock; yet the job is started even though these purchased materials have not been received or have not been ordered. Interruptions, delays, confusion, and high costs may be incurred.
- Without prior planning, the need for participation by other works in the production department is not recognized sufficiently in advance to provide for the right kind of manning at the proper times.
- Without prior detailed knowledge of the job components, it is difficult for a craft foreman to estimate the number of men required to perform the work.
STEPS FOR EFFECTIVE MAINTENANCE PLANNING:
In order to obtain effective planning, it is apparent that accurate and consistent time standards must be developed for each maintenance function. Proper planning includes a determination of what the job costs should be if the job is performed as planned. Known techniques for determining standard time values involve time study or the use of motion-time values, which result in time development based upon technical analysis of the work involved. Owing to the variable, no repetitive nature of maintenance work, a great deal of technical study is required before the standard data assembled represent sufficient coverage of the work to be performed so that effective planning can result. Although an admittedly difficult task, this approach has been used by some of the larger companies, and complete and accurate time values have been established for most maintenance work.
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Effective maintenance planning assumes that the plan can be used. In order to apply some of the more modern techniques such as arrow diagrams to maintenance work, each segment of the job must be estimated accurately. The various craft requirements must be known so that each craft can be scheduled within acceptable time limits. Backlog controls, which result in proper personnel alignments, require accurate determination of the hours in the work backlog by craft.
Effective preventive maintenance programs require scheduling of time to perform the work and the coordination of preventive maintenance time with the various maintenance, repair, and construction work that flows in and out of the maintenance department on a variable basis.
SCHEDULE OF MAINTENANCE PROGRAMME:
Every organization should have a proper design of its maintenance schedule. The following are four important aspects of maintenance schedule:
A.) Maintenance Responsibility:
- Defining maintenance function
- Establishing relation with functional areas of management.
- Design of schedule for maintenance management.
B.) Designing Organization Structure:
- Design of formal structure of organization
- Delegation of authority & Responsibility
- Defining the role of each authority in maintenance management.
C.) The Work Programme & Schedule:
- Procedure for work execution
- Authorization required
- Work classification
- Work cost estimates
- Records, Charts
- Internal Maintenance
D.) Planning and Scheduling:
- Daily, Weekly, long-range
- Job Planner
- Materials, Methods and Manpower planning
- Routine work Scheduling
- Planned work Scheduling
E.) Preventive Maintenance:
- Programme and procedures
F.) Control and Standards
- Job standards
- Materials standards
- Cost standards
- Work simplification
- Work sampling
- Measurement of results
G.) FUNCTIONAL MAINTENACE:
- Finance Department
- Production Department
- Marketing Department
- Human Resources Department.
FUNCTIONS OF MAINTENANCE DEPARTMENT
It is observed that the planning personnel would be part of the maintenance staff responsible for the planning, scheduling, and clerical functions involved in proper maintenance control. The following are key functions of maintenance department:
- Work order system.
- Planning and estimating.
- Backlog control.
- Performance reports.
Supervisor plays a crucial role in maintenance department. The generation of a maintenance plan to be used for labor scheduling and control requires the determination of the time required to perform the work. The most common tool used in maintenance is the supervisor’s estimate, which is employed for this purpose. While it is fairly easy to estimate the cost of materials, the amount of time required to perform work is another matter. A labor estimate can be defined as the probable time required performing a job based on the best judgment of the person making the estimate. The personal experience, knowledge, and ability of the estimator will affect the quality of the estimate.
The disadvantages of supervisory estimates include the following:
- Estimates are usually inconsistent and inaccurate.
- Estimates vary in accuracy with different estimators.
- Training of estimators is not easy.
- Verification is almost impossible.
HISTORICAL DATA METHOD
Historical data method is used in this approach is rather simple. In this method, completed work orders are analyzed, and average times are established for various categories or natural groupings of maintenance work. For example, all small maintenance jobs can be classified as those jobs, which should require less than three hours. The time to perform these jobs, based on past records, could indicate an average of 2.10 hours. The next natural grouping may be maintenance jobs that require a maximum of four hours. The average time for these jobs might be 2.3 hours.
In this fashion, all maintenance work is classified on past performance. In addition, repeat jobs can be thoroughly analyzed until an average time for the individual repetitive job can be obtained. New work is initially placed into one of the developed groupings on a judgment basis and later verified.
- Average time values reflect past costs and problems rather than accurate cost projections.
- Alternate methods are difficult to compare.
- New work is difficult to assess.
- Past inadequacies become built into the system.
- The maintenance manager must ask himself if he makes plans, directs, instructs, evaluates performance, and makes decisions for his function in such a way that maintenance contributes to these objectives.
- Maintenance should be performed to protect capital investment, to keep equipment operating at a high level of performance, and to prevent injury to life and damage to property
- The goal of the maintenance manager should be to develop an adequate number of preventive maintenance tasks and by so doing to prevent equipment or facility failures and to effect other reductions in “happening” or no routine maintenance for the purpose of obtaining the highest operating efficiency at the lowest operational cost consistent with safety requirements.
- Maintenance manager compares the routine painting of exposed structural members with a breakdown in production equipment.
- Maintenance managers do not plan for the effective use of their manpower and equipment. Some of them back up line production; some support jobbing and intermittent production operations; and some assure the continued flow of service to customers.
- The maintenance manager needs reports, which are timely, and this means reports received periodically which will assure him that the maintenance program is progressing in the way that he has planned it. These reports must enable him to initiate corrective action to get the program back on the track when needed. These reports must be timely because he must have the data at specific intervals to make the right decision. Examine the maintenance workload; how detailed this is to be must be decided by each manager.
- Establish a work order system for dispatching the work, which is planned for a certain period.
- Re-evaluate planning techniques to determine whether the men will be able to perform the work as planned.
- Determine whether a record-keeping system is necessary to ascertain whether realistic and economic maintenance practices are being followed.
- Develop reports, which will help in:
- Maintaining production.
- Controlling operations.
- Planning manpower requirements.
- Correcting or modifying work assignments.
- Evaluating personnel performance.
- Establishing budgetary controls.
Preventive maintenance is a common tool for both production and maintenance to use in achieving maximum production at minimum repair cost. Both production and maintenance have the same objective: to produce a quality product at maximum efficiency and minimum cost. Production department managers must realize that maintenance is a key to continuous production. Through the use of good preventive maintenance procedures in which the work of both production and maintenance personnel is well coordinated, production downtime can be minimized and costly repairs and interruptions in planned maintenance and production schedules can be eliminated. There has been some conflict in the past between production and maintenance people over the proper methods of achieving maximum machine performance. The usual practice was to operate production equipment at maximum performance for the longest possible time until breakdown
Occurred and then make hurried repairs to get back into production. In most cases these repairs involved unscheduled work.
One of the main objectives of preventive maintenance is to find any condition that may cause machine failure before such a break-down occurs. This makes it possible to plan and schedule maintenance work with the least amount of interruption and plan production volume with a higher rate of accuracy. Today maintenance people prefer to perform their work on a scheduled basis and get away from the “crash” situation that accompanies breakdowns. They thereby increase the utilization of available manpower and machine time and prolong equipment life. Because of the increased complexity and high initial cost of machinery, it has become essential to have a formal or planned maintenance program. However, there isn’t sufficient justification to have a planned program for every piece of machinery in a plant, nor is it -possible to eliminate all breakdowns; but we can minimize interruptions in the work schedule. Concentrating on those units that are considered as “critical units” does this.
A unit qualifies as a critical unit if:
- Failure of the unit would endanger health or safety of operating personnel.
- Failure would affect quality of the product.
- Failure would stop production.
- Capital investment for a unit is high.
When the critical-unit concept is applied to preventive maintenance, the basic principles of value engineering can be brought to bear—that is, we can place primary emphasis on those units in a process that require critical maintenance and which, through good maintenance, will provide the greatest return in reduced downtime and high production. For those units which do not qualify as critical, random or routine maintenance may be all that is required for satisfactory operation. The basic idea is to concentrate the preventive maintenance program on select units and inspect these units thoroughly and conscientiously.
PROCEDURE OF PREVENTIVE MAINTENANCE SYSTEM
- Periodic inspections of machinery, utilities, and buildings. The frequency of inspections is determined by experience or, in the case of new equipment, by the manufacturer’s recommendations until experience is gamed.
- Reporting of breakdowns or mechanical failures so that they can be analyzed and corrective maintenance action can be taken to assure that they will not become repetitive.
- A certain number of forms and records are necessary for any preventive maintenance system. The number of forms needed largely depends on the size of the plant. What follows is a detailed description of the various forms and procedures we use.
The preventive maintenance clerk routes the inspection order as follows:
- At the first of each month the inspection orders are pulled from the file, and the unit numbers are recorded on the control sheet
- When all inspection orders are returned to the clerk after the inspections are made, they are checked off on the control sheet, showing that inspections scheduled have been completed.
- Unit numbers of inspection orders, which are returned with job sheets, are checked off on the control sheet as completed and recorded under the column “jobs resulting.” When these jobs have been completed and job sheets have been returned to the clerk, the unit number is checked off the jobs-resulting column.
- From this control sheet the clerk is now in a position to prepare his monthly preventive maintenance report.
- A new control sheet is started each month. The “incompletes” are brought forward with a pencil of a different color so that they will not be counted again as inspections scheduled or jobs resulting.
- Completed inspection orders are filed by department according to the next inspection is scheduled.
The routing of the inspection order by the Production Department follows different channels, depending on who makes the inspection.
- After receiving the inspection orders from the preventive maintenance clerk, the production department manager assigns one of his men or requests the Maintenance Department to make the inspection. In either case, qualified people must perform inspections.
- The inspector uses the inspection order card as a guide in making the inspection. He checks the appropriate spaces on the front of the card and makes remarks on the reverse side for such things as cleaning, adjustments, or descriptions of work to be requested on the job sheet. Completed inspection orders are returned to the department manager.
- Job sheets are prepared by the department manager for items marked “poor” on the inspection orders. Job sheets for preventive maintenance are attached to inspection orders and forwarded to the preventive maintenance clerk; the job resulting is recorded on the control sheet; and after this is done, the job sheets are then sent to the planner.
If an inspection requires special skills, technical abilities, or extensive work such as dismantling a machine, a job sheet is prepared authorizing such an inspection and is forwarded with the inspection order to the planner. The job sheet is then handled through the normal procedure. The mechanic making the inspection completes the inspection order form and returns the form to the planner. During the inspection the inspector is expected to lubricate, adjust, and make minor repairs. If work is required after the inspection has been made by the mechanic, the planner returns the inspection order to the department manager. If the department manager feels that the work suggested on the inspection card is needed, he will issue a job sheet for the necessary repairs.
Corrective maintenance is the study of all equipment failures and break-downs to determine what action is needed to prevent reoccurrences. The procedure is such that whenever a breakdown occurs, it is studied as to the cause, what repairs were made, and what further action is needed to assure that the breakdown will not become repetitive. In general this last makes necessary a review of the breakdowns with respect to the following:
- Changing the process.
- Redesigning the component that failed.
- Replacing it with an unproven part or an entirely new machine.
- Improving preventive maintenance procedures—for example, by performing lubrication according to a schedule or readjusting the frequency and content of the inspection.
- Reviewing and changing operational procedures—for instance, by training operators in the proper operation of the particular unit or change load on the unit.
The analysis of breakdown report is filled out each month by all plants. This method of reporting breakdowns has proven to be very effective where used properly for reviewing breakdowns and determining measures necessary to assure that breakdowns will not become repetitive. This report will direct attention to the troublesome areas where review for improvement is most needed.
The end result of good preventive maintenance is an aggressive corrective maintenance program. We therefore found it imperative that corrective maintenance be adopted as a formal procedure in each plant in an effort to eliminate repetitive breakdowns. Corrective maintenance will not eliminate all breakdowns; however, it will hi tune, with adequate follow-up, eliminate the repetitive breakdowns. By reducing downtime and cutting down the number of breakdowns, corrective maintenance will increase production and open up avenues of process change and equipment redesign or replacement.
It is the responsibility of both Production and Engineering and Maintenance to follow up breakdowns and take the corrective action needed. But as with the preventive maintenance program, it is the responsibility of the manager of engineering and maintenance to administer and coordinate this effort. Basically the flow is as follows:
Flow of Corrective Maintenance:
- The operating department originates the breakdown report with a full description of corrective maintenance required.
- Since it is the responsibility of the manager of engineering and maintenance to administer and coordinate the corrective maintenance function, he must receive and review all breakdown reports, while paying attention to the engineering and maintenance aspect of corrective maintenance.
- The breakdown reports must be filed by department for additional consultation with the particular department manager.
- During the weekly planning and scheduling meeting with the planners and department managers, the follow-up of corrective maintenance is coordinated; this includes writing the necessary job sheets, if any are needed, and assigning priority to the work.
- At the end of the month, the monthly breakdown of analysis report must be written and distributed before the tenth of the following month.
Most Companies are probably receiving 50 paisa worth of labor and materials for every rupee of maintenance expenditure. This situation can exist alongside operations that time study methods and other analytical devices have developed to high efficiencies.
For instance, consider what the average maintenance worker must contend with in the performance of a normal day’s work. He must alternately search for or hide from his foreman depending upon whether work is available or not. He must line up and wait for his job assignments morning and afternoon. He must join the queue at the tool crib, the stores, the time clock, and even at the machine he wants to use. He must be the operator to let him have the machine that is limping but still producing. All this is frustrating for a conscientious man and for the not-so-conscientious provides many an opportunity for goldbricking.
For example, in a factory, 30,000 observations of a maintenance force of 400 people, taken over six months, it was found that the average mechanic was working only 53 per cent of the time. The startling fact was that when he was working, it was in excess of 100 per cent performance. Thus it would seem that if he is given the opportunity, he will turn in a fair day’s work.
This inefficiency in labor utilization almost invariably has its counter-part in materials wastage. It shows up in various ways: stores withdrawals in excess of needs; substitution of new parts when old parts still have useful life; constant replacement of parts due to inefficient repairs; having nuts, bolts, clamps, washers, welding rods, and so on lying around the plant in various nooks and crannies.
A FIVE-FOLD PROGRAM:
To realize efficient maintenance at a reasonable cost, the following steps must be taken:
- Measurement through quantification of work and duration.
- Planning and scheduling: determining in what order and by whom the work should be done.
- Training; methods; environment; provision for skills, tools, knowledge, and appropriate working conditions.
- Preventive maintenance: pre-scheduling of repetitive work.
- Corrective maintenance: seeing that weak components -are designed out of equipment.
These steps are closely interrelated, and any program that specializes in one without due consideration of the others will yield only a fraction of the anticipated results. For example, it is senseless to demand good scheduling from a foreman if he doesn’t know how many men to send out to the job for how long. It is unrealistic to develop accurate measurement for a foreman who must send out unskilled men who lack the proper tools to perform the work. It is a worthless venture to burden the foreman with repetitive repairs on under designed equipment.
Since it is usually necessary to start a program in a modest way, emphasis on measurement, although not the obvious, is the logical choice. Good measurement in conjunction with the supporting administrative functions is essential in developing labor effectiveness, efficient planning and scheduling, workload factors, accurate costs, and data for analytical preventive maintenance and corrective maintenance. It will also indirectly indicate the need, if it exists, for training and methods studies. Thus the orderly development of a long-range, broad program has as its first prerequisite good measurement.
The usual objection to a program of this nature is that the development of tune standards accurate enough to be useful is too expensive or even that it is impossible to develop such accurate standards for maintenance work. Both these statements are fallacious. New methods have been devised to obtain maintenance standards (predetermined or self-developed) that are inexpensive and produce results rapidly.
USING DATA PROCESSING IN MAINTENANCE
A Plant Preventive Maintenance operation lends itself admirably to the application of data processing. This is true because the basic elements of the function—record keeping, scheduling, and reporting— can be readily systematized and programmed on modern data-processing equipment.
Plant equipment requires periodic maintenance if it is to be kept in efficient operating condition. Breakdowns and costly repairs can be avoided by a well-planned servicing schedule. This can be a complex affair, because of the great volume of items and the varied checking intervals required. There are also wide variations in the degree of thorough-ness called for. In any comprehensive maintenance system there must also be regular reporting of the dates of servicing and of emergency calls for each item.
The type of maintenance program will depend on the nature and magnitude of the function. For purposes of this discussion, it will be assumed that a preventive maintenance program is being instituted for a modern electronics plant and that this program is to be responsible for the building, building equipment, processing equipment, chilled-water units, sanitary and industrial waste treatment, and the appearance of buildings and grounds. The program to be described in this unit can be adapted, however, to any industry for any type of equipment.
Reporting is a management tool, and it provides the manager with the means for evaluating current programs and for reporting changes hi these programs to top management. The secret of this tool is that it allows him to group relevant bits of information for analyzing time and work done and for evaluating the dollars spent. The reports he receives must provide him with a feedback of related performance data, which will be useful in:
- Maintaining production.
- Controlling operations.
- Planning manpower requirements.
- Correcting or modifying work assignments.
- Evaluating personnel performance.
- Establishing budgetary control.
If reports fail to satisfy his needs, he must review them carefully for correction and revision and try them again. If they fail again to provide the necessary data, he must scrap them and try a new approach. Reports that are well conceived can serve as an invaluable management tool. The speed and versatility of electronic equipment offer an opportunity to quickly rework data into new relationships. This also challenges the imagination with new and expanded concepts of information reporting, but the practical value of each report must be determined by a critical review of its actual contribution in controlling the maintenance program.
Let us examine a typical maintenance control system to see how data are developed and used for measuring and appraising maintenance performance. This maintenance control system has eight phases: routine maintenance, no routine maintenance, advanced planning, daily scheduling, daily activities, recording maintenance data, and management reporting, and accumulating personal statistics.
Objective for a suitable system:
The initial objectives for a suitable system would be as follows:
- To keep historical records of all maintenance activity and accumulated labor and materials costs for each item.
- To provide schedules to initiate work orders for those items re-quiring regular preventive maintenance.
- To generate management reports showing costs by area, department, and item.
Before this system can be installed, it is necessary to analyze the data required and organize it in usable form. This comprehensive groundwork is done in the following sequence over a period of months:
- All items are identified on which maintenance is required.
- Determination is made of those items to be included in preventive maintenance schedules, and times are then established for them.
- A coding system is devised for the selected items to permit scheduling of maintenance for either complete units of equipment or components of them.
- Card forms are designed for use in all phases of the computerized program.
- The types and formats of the reports are determined.
- A program is written for a computer which will process all the data.
- Punched cards are made which contain preventive maintenance work orders for each item to be scheduled.
- All items to be scheduled are numbered.
- The program is instituted.
As in all computer operations, the data-processing functions fall into the three categories of input of information, central processing of information, and output of information. The input information is that which originates, updates, and controls the schedule spread of the program. When an item is introduced to the program, the system records a new item number, the frequencies of preventive maintenance desired, the estimate time for each frequency (route code), a short basic description, and any other desired information. This master record is updated by processing one of the following change cards:
- A new record origination, to add a frequency to an existing item.
- A deletion, to remove all or a portion of an item.
- A data change, to revise frequencies, building locations, departments responsible, or other basic information.
- A labor claim and completed service calls.
After all of this input information has been recorded on an input magnetic tape, the next step is to collate the information with that on the existing master tape. This is the central-processing stage of the computer process. The new information results in rescheduling, conversion of new labor-hours into dollars, and the calculation and posting of materials costs by category. Estimated versus actual times are compared for all in-house maintenance jobs—by department and by individual worker.
The final step in the data processing system is the delivery of the output information in the form of legible documents. The principal ones are:
- Prepunched preventive maintenance schedule cards, which indicate which jobs are being performed and serve as source documents for management activity reports.
- Prepunched maintenance labor and materials cards, which serve as source documents for updating preventive scheduling, performance evaluation, breakdown analysis, and contractor expenditures.
- Work orders, which provide detailed instructions for the maintenance which the mechanic is to perform.
- Workload forecasts, which are used to plan manpower requirements. This is a highly significant management tool because it makes possible scientific manpower planning.
- Reports of evaluation of performance—by department and by individual worker.
- Reports of backlogs of jobs not performed as scheduled and therefore to be given priority. The maintenance-backlog report informs the area manager as well as the maintenance manager that the workload for the previous period was not met. These jobs are given priority hi the next maintenance load forecast.
- Cost reports, which indicate areas for future economics?
In addition to this basic preventive maintenance data-processing program, a number of special programs may be added for other elements of a maintenance function. For example, a perpetual inventory and automatic ordering of maintenance supplies may be incorporated in a permanent program. Such a system would keep track of stock on hand and issue a purchase order for replenishment when the minimum supply is not available. This is done in the following steps:
- Supply requisitions automatically reduce the inventory count.
- Order cards are initiated when the inventory count signals that the order point has been reached.
- An on-order condition is posted when an order has been initiated.
- Receipts to stock are posted when orders arrive, thus increasing the inventory count and removing the on-order posting.
A workable maintenance scheduling system must make provision for scheduling of additional or special jobs as the need arises. New job requirements are first analyzed for scope and time involved, urgency and schedule date, and supply needs. The data are then registered on punched cards, which are added to the existing workload forecast. On the basis of the adjusted forecast, the manager decides whether to schedule overtime, request temporary help, reschedule other jobs, or make some of this man-power available on loan to other departments.
Short Range Programs:
In a shorter-range program, jobs are scheduled up to eight weeks in advance of the requested completion date. In preparing a program, an estimate must be made of the number of hours necessary to complete each segment of the job; a completion target date must be assigned; and the necessary personnel must be allocated. The programmed computer then performs the following operations:
- Establishment of the job starting date, calculated by subtracting the minimum lead tune from the completion target date.
- Printing of job schedules for engineering, layout, construction, and rearrangement.
- Printing of job schedules for individuals for the next eight-week period.
Long Range Programs:
For long-range programs, the program evaluation and review technique (PERT) is used. Many facets must be phased or dovetailed for each project. The principles of this approach are:
- Each segment of the project is projected in time with a direct relationship to other segments which may have an effect on it.
- Possible actions which may cause a reaction of any given segment of the project are denned.
- Time, the critical factor in causing an action, is estimated.
Once the actions and alternative actions have been gathered, their relationship to each other established, and the time factors applied to each segment, it is possible to -arrive at a suggested starting date by working backward from the required completion date.
The advances of modern industrial production have resulted in complex plant facilities, which make the application of data processing to maintenance a necessity. Preventive maintenance, so scheduled, will keep a plant operating efficiently and reliably around the clock.
This unit deals with the size and complexity of the maintenance operation must be considered in the approach to maintenance control. On the other hand, a maintenance force in excess of 25 to 30 workers presents complications from a coordination and planning standpoint. Unfortunately the informal control approach is too often used in large, complex organizations even though the magnitude of the operation may have long since exceeded manageable dimensions.
- What are the objectives of plant maintenance?
- What is the difference between preventive maintenance and corrective maintenance.
- Write a note on tasks of maintenance manager.
- B.S.Goel, Production and Operations Management, Pragati Prakashan, Meerut, 2002.
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- Mahadevan, “Operations Management Theory and Practice” Second Edition, Pearson, New Delhi.
- James R. Evans, David A. Collier, “Operations Management Concepts, Techniques and Applications”, Latest Edition, Cengage Learning India Pvt. Ltd., New Delhi.
- Aswathappa, K. Shridhar Bhat, “Production and Operations Management”, Latest Edition, Himalaya Publishing House, Mumbai